Hydraulic fracturing is among the varied oilfield operations used to produce petroleum products from underground formations. In hydraulic fracturing, a fluid is pumped down a wellbore at a flow rate and pressure sufficient to fracture a subterranean formation. After the fracture is created or, optionally, in conjunction with the creation of the fracture, proppants may be injected into the wellbore and into the fracture. The proppant is a particulate material added to the pumped fluid to produce a slurry. The proppant within the fracturing fluid forms a proppant pack to prevent the fracture from closing when pressure is released, providing improved flow of recoverable fluids, i.e. oil, gas, or water. The success of hydraulic fracturing treatment is related to the fracture conductivity which is the ability of fluids to flow from the formation through the proppant pack. In other words, the proppant pack or matrix may have a high permeability relative to the formation for fluid to flow with low resistance to the wellbore. Permeability of the proppant matrix may be increased through distribution of proppant and non-proppant materials within the fracture to increase porosity within the fracture.
Some approaches to hydraulic fracturing conductivity have constructed proppant clusters in the fracture, as opposed to constructing a continuous proppant pack. These methods may alternate stages of proppant-laden and proppant free fracturing fluids to create proppant clusters in the fracture and open channels between them for formation fluids to flow. Thus, the fracturing treatments result in a heterogeneous proppant placement (HPP) and a “room and pillar” configuration in the fracture, rather than a homogeneous proppant placement and consolidated proppant pack. The amount of proppant deposited in the fracture during each HPP stage is modulated by varying the fluid transport characteristics, such as viscosity and elasticity; the proppant densities, diameters, and concentrations; and the fracturing fluid injection rate.
Pumping this slurry at the appropriate flow rate and pressure to create and maintain the fracture of rock strata is a severe pump duty. In fracturing operations each fracturing pump may pump up to twenty barrels per minute at pressures up to 20,000 psi. The fracturing pumps for this application are quite large and are frequently moved to the oilfield on semi-trailer trucks or the like.
In large fracturing operations, it is common to have a common manifold, called a missile, missile trailer or manifold trailer, connected to multiple fracturing pumps. The manifold trailer distributes the fracturing fluid at low pressure from a blender to the fracturing pumps. The fracturing pumps pressurize the slurry, which is collected by the manifold trailer from the fracturing pumps to deliver downhole into a wellbore. Valves on the manifold trailer connected to the fracturing pumps are completely manual in current fracturing operations. In current operations the fracturing pumps are manually connected to the manifold trailer and pairs of fracturing pumps and valves are manually identified prior to pumping.
The fracturing pumps are independent units plumbed to the manifold trailer at a job site of a fracturing operation. A particular pump will likely be hooked up differently to the manifold trailer at different job sites. A sufficient number of pumps are connected to the manifold trailer to produce a desired volume and pressure output. For example, some fracturing jobs have up to 36 pumps, each of which may be connected to distinct valves on the manifold trailer.
The manual connection between each pump and manifold inlet/outlet of the valves may result in miscommunication between a pump operator and an outside supervisor who opens and closes the valves on the manifold trailer. The miscommunication of the association of the valve to the pump may cause the wrong valves to be opened and closed. Opening the wrong valve causes the pump to pump against a closed valve and over pressurize the line causing service quality, health, safety, and environmental risks and financial loss as well as downtime for the fracturing operation. Currently, no known method exists to automatically pair pumps to manifold trailer valves to avoid potential miscommunication and opening or closing of unintended valves.